windows-threadpool-sys

Memory-safe Rust access to the Windows thread pool APIs.

The Windows thread pool lets applications dispatch work and wait on operating system objects without permanently dedicating application threads to those waits. This is particularly useful for Windows services and components that need to become inexpensive when idle.

windows-threadpool-sys will build on the raw API declarations from windows-sys and provide a Rust programming model with explicit callback, cancellation, and resource lifetime rules.

Status

The crate is in its initial development stage and does not yet expose its thread pool API. The intended scope and motivation are recorded in DESIGN-NOTES.md, and current implementation work is tracked in CHECKLIST.md.

Platform support

Primarily Windows only: the public API and implementation of this crate target Windows, CI builds/tests/lints it exclusively on Windows, and platform-specific code lives behind cfg(windows). The workspace's wtf-string crate is the exception -- its portable core has no cfg(windows) gating, so CI additionally builds, tests, and lints it on Linux and macOS.

Crate naming

The -sys suffix here does not carry its usual ecosystem meaning. A -sys crate is normally raw FFI declarations with no abstraction over them; every windows-*-sys crate in this workspace instead wraps a great deal of unsafe, and takes its declarations from windows-sys rather than making its own.

What the suffix marks is a layer:

• windows-*-sys -- makes an existing Win32 API memory-safe without adding policy. It schedules nothing, picks no delivery model, and reports the platform's outcomes unnormalised.
• no suffix -- decides something Win32 has no equivalent of. windows-waitable-queues is the worked example: it chooses a slot protocol, an overflow policy, and a signalling discipline, so calling it -sys would misdescribe how much it decides on the caller's behalf.

So the presence of unsafe wrappers is not evidence either way -- it is the job description of the first kind. The distinction is policy, and the suffix is the only signal a reader has for how much a crate decides for them.

This section is the statement of record. The convention governs published crate names, so it belongs where a reader meets the crates rather than only in the design notes.

Build

Requires Rust 1.98 or newer.

cargo fmt --all --check
cargo build --workspace --all-targets --all-features --locked
cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
cargo test --workspace --all-features --locked

Release

Merging conventional commits to main allows release-please to open or update release PRs. Merging a release PR creates a v<version> tag, which triggers the crates.io publish workflow.